Ballistics, 2nd Edition

161Ammunition Design Practice

the sabot, τ. Similarly, on the sabot, we have the net internal stress, (dσ

zs

/dz)∆z; the inertial

resistance to acceleration, ρ

s

V

s

a; the shear stress imparted by the sub-projectile, τ; and the

component of pressure in the axial (z) direction. We proceed by initially nding an expres-

sion for the volume of the sabot free body. Details of this derivation are found in Ref. [6].

The incremental volume of the sabot can be shown as follows:

V

ssp

=−









∆

π

Rz

Rz

22

()

(4.158)

Double-ramp sabot

Penetrator

σ

1

τ

p

s

Shear

stress

Axial distance

FIGURE 4.27

Shear stress variation in a double ramp-type sabot.

r

τ

σ

zp

σ

zp

dσ

zp

R

P

dz

Δ

z

+

Δz

FIGURE 4.28